What is the downside of using a commercial lender to purchase, my own cash to rehab, and then refinancing?  

From outside, that would be my biggest concern with them.

More consolidation by the biggest banks and asset management company. 

The biggest reward of owning and managing vacation rentals is much greater than financial; the friendships I have made with people around the country are priceless.  

My biggest mistake was thinking that I could lay down new LVP on the main floor of my last house hack, 1 month out of shoulder surgery and I quickly pivoted to a local professional.

I think the biggest issues I've had in the past with other programs is that it's a one size fits all and that's simply not the case.

Some potential downsides include giving up more profit and possible disagreements on project decisions.

This is the biggest load of crap so-called "SEO experts" will tell you.

The biggest impact could be in the negative PR though, as sometimes perception becomes reality, factual or not. 

You as the business owner are ultimately responsible (legally and ethically) for the actions taken under that mantle.As the OP stated, this is a new business relationship, and in my opinion there is much more downside to being laissez faire at this point as opposed to "hands on."